6 research outputs found
Temperature-Sensitive Transitions below LCST in Amphiphilic Dendritic Assemblies: Host–Guest Implications
OligoÂ(ethylene
glycol)-decorated supramolecular assemblies have
been of great interest due to their charge-neutral character and thus
their propensity to avoid nonspecific interactions. These systems
are known to exhibit a macroscopic temperature-sensitive transition,
where the assembly phase-separates from the aqueous phase at higher
temperatures. While this so-called lower critical solution temperature
(LCST) behavior has been well-studied, there have been no studies
on the fate of these supramolecular assemblies below this transition
temperature. The work here brings to light the presence of a second,
sub-LCST transition, observed well below the LCST of oligoÂ(ethylene
glycol) (OEG)-based dendrons, where the host–guest properties
of the assembly are significantly altered. This sub-LCST transition
is accompanied by changes in the guest encapsulation stability and
dynamics of host exchange
Electrostatic Control of Peptide Side-Chain Reactivity Using Amphiphilic Homopolymer-Based Supramolecular Assemblies
Supramolecular
assemblies formed by amphiphilic homopolymers with
negatively charged groups in the hydrophilic segment have been designed
to enable high labeling selectivity toward reactive side chain functional
groups in peptides. The negatively charged interiors of the supramolecular
assemblies are found to block the reactivity of protonated amines
that would otherwise be reactive in aqueous solution, while maintaining
the reactivity of nonprotonated amines. Simple changes to the pH of
the assemblies’ interiors allow control over the reactivity
of different functional groups in a manner that is dependent on the
p<i>K</i><sub>a</sub> of a given peptide functional group.
The labeling studies carried out in positively charged supramolecular
assemblies and free buffer solution show that, even when the amine
is protonated, labeling selectivity exists only when complementary
electrostatic interactions are present, thereby demonstrating the
electrostatically controlled nature of these reactions
Polymer-mediated ternary supramolecular interactions for sensitive detection of peptides
Electrostatic Control of Peptide Side-Chain Reactivity Using Amphiphilic Homopolymer-Based Supramolecular Assemblies
Supramolecular assemblies formed by amphiphilic homopolymers with negatively charged groups in the hydrophilic segment have been designed to enable high labeling selectivity towards reactive side chain functional groups in peptides. The negatively-charged interiors of the supramolecular assemblies are found to block the reactivity of protonated amines that would otherwise be reactive in aqueous solution, while maintaining the reactivity of non-protonated amines. Simple changes to the pH of the assemblies’ interiors allow control over the reactivity of different functional groups in a manner that is dependent on the pK(a) of a given peptide functional group. The labeling studies carried out in positively charged supramolecular assemblies and free buffer solution show that, even when the amine is protonated, labeling selectivity exists only when complementary electrostatic interactions are present, thereby demonstrating the electrostatically controlled nature of these reactions